Oil continuous emulsions containing gases and a dispersed aqueous phase are customarily degassed before being subjected to a dehydrating operation involving resolving the emulsion by electric field treatment. Such resolution involves introducing the emulsions directly into an electric field of sufficient intensity to coalesce the suspended droplets of the dispersed phase into masses of sufficient size to gravitate from the oil. Gas may form due to pressure drops, heating and other causes or may be initially present in the emulsion being treated. Removal of the gas is desirable to obviate problems caused by gas passing through the electrode area.
It is also known to mix a quantity of water with incoming crude oil so that a more complete removal of the salt from the oil may be accomplished during the dehydration operation.
It is further known to resolve and dehydrate emulsions without the use of an electric field.
More specifically, it is known to carry out degassing and resolving operations in separate side by side zones of a treating vessel. Such systems are shown in U.S. Pat. No. 3,207,686 to Howell R. Jarvis and William L. Shirley and U.S. Pat. No. 3,458,429 to Frederick D. Watson and Weldon D. Mayse. It is also known to provide a gas separation zone below the level of the emulsion resolving zone. This is shown in U.S. Pat. No. 3,347,773 to Delber W. Turner.
It is an object of this invention to provide an improved degassing-distributing system which will efficiently remove gas evolved in a system where crude oil is preheated and a pressure drop is created by a mixing valve in the operation of a dehydrating-desalting process. It is a further object of this invention to provide an improved dehydrating and degassing apparatus employing said improved degassing-distributing system.
Other objects of the invention will be evident to those skilled in the art in the course of the following description.